Muffler



March 28, 1939.

W.A. MORRISON MUFFLER Filed March 18, 1937 7' a? T 18 2 g 3; 4

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INVENTORI m'lhanzjl Mqrm 50m 'H s ATTCRNEY.

Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE MUFFLER Application March 18, 1937, Serial No. 131,592

1 Claim.

This invention relates to mufflers, and more particularly to a detachable exhaust silencer for fluid actuated tools.

The exhaust noise of a percussion tool like a pneumatic riveter or paving breaker is probably less than the noise made by the blows of the hammer element upon the anvil block or working implement, but it is more easily suppressed, and to the extent that it is eliminated the operation of the tool is made less noisy.

It is an object of this invention to provide a simple and inexpensive muffler to suppress the exhaust sounds from fluid pressure operated tools.

A further object is to make the device readily l5 attachable to tools already inservice, and to make it detachable so that it may be removed if and when the reduced noise is of no importance.

In the accompanying drawing, Figure 1 shows a longitudinal section of a practical embodiment of the invention applied to a fluid actuated tool 1 of conventional design, and

Figure 2 is a view of the muffler from the rear. Referring to the drawing a casing l0, preferably made of a moulded resilient and impervious material such as soft rubber, is attached to the side of a pneumatic paving breaker l2, so that an entrance opening l4 near an end of the casing is in registry with an exhaust port l6 of the paving breaker.

The muffler, in this instance, is clamped or attached to the paving breaker l2 by straps or bands l8 fastened in any convenient manner to the mufller and equipped with suitable buckles or grips 20. At the lower end of the mufller the resilient wall is pierced with a number of outlet ports 22 through which the exhaust fluid may escape.

An expansion chamber 24 is formed in the inside of the muffler, and bafiling means may fill the chamber 24 and overlies the outlet 22 to prevent a direct rush of the fluid from the inlet I4 to the outlet 22. Rock wool, metal wool, sponge, 5 or other fibrous material, designated generally as 26 makes a suitable baffle.

For best results the mufller should be made to fit snugly, without distortion, against the outer Wall of the tool, and consequently it is preferable 0 that different models of mufflers be provided for corresponding models of tools.

In the case illustrated the tool has a protruding lip or guide 30 defining one wall of the ex haust passage l6, and the back 28 of the mufiler 5 I0 is shaped to conform with the contour of the paving breaker and has a depression 32 to accommodate the lip.

In practice when the piston of the tool uncovers the exhaust port l6 pressure fluid passes 20 into the muffler through the opening I, expands in the baffled chamber 24 and escapes through the exit ports 22 with pulsations of reduced in tensity and with consequent reduction in noise.

I claim:

An exhaust mufller for fluid pressure operated machines, comprising a casing of resilient material, a wall on the casing shaped to conform with the contour of the machine and having an opening at one end adapted to overlie the exhaust 30 outlet of the machine, an expansion chamber in the casing, an exit passageway from the chamber located at the other end of the casing, baffling means in the chamber overlying the exit passageway, and straps on the casing to attach 35 the casing to the machine.

WILLIAM A. MORRISON. 

